CN105189063A - curved wood laminate and the curved moldings made from it - Google Patents

Abstract

The invention relates to a bendable curved wood laminate with an intermediate layer (2), in particular forming a central layer, having a first and a second surface side, wherein a first outer wood layer (3) is arranged on the first surface side and a second outer wood layer (4) is arranged on the second surface side. According to the invention, the first and/or second outer wood layers (3, 4) consist of balsa plywood.

Description

curved wood laminate and the curved moldings made from it

technical field

The invention relates to a bendable (or bent into a molded part after processing) bent wood laminate (Biegeholzlaminat) with an intermediate layer (in particular forming a central layer) according to claim 1, having a first and a second Two (facing away from each other) surface sides, wherein a first wood layer is arranged, in particular glued, on the first surface side and a second wood layer is arranged, in particular glued, on the second side. Furthermore, the invention relates to a bent molded part made of such a bent wood laminate, wherein the bent wood laminate of the bent molded part according to claim 13 is shaped according to the processed shape, in particular due to the arrangement of at least A covering that is not only bendable but also reinforced.

Background technique

WO 2009/138197 A1, outside the field, studies inflexible shaped articles made of balsa wood, wherein as an intermediate step for the manufacture of such shaped articles it is known that the manufacture is formed from a plurality of peeled plies stacked one above the other inflexible blocks and process them into transverse timber.

From DE20108858U1 is disclosed an inflexible furniture-making board having as middle or core layer an extremely thick balsa wood board compared to the other layers, the fibers of which are aligned perpendicular to the plane of the board, thus resulting in the use in land vehicles and Rigid lightweight manufacturing panels for aircraft. The above-mentioned intermediate layer of balsa wood can be solid wood, on the outside of which a layer of plywood is provided for decorative purposes.

EP2119540A1, which is also outside the field, deals with rigid shaped parts formed from balsa wood, wherein the shaped part is constructed from a plurality of small balsa wood segments, which are connected to each other with an adhesive in between. Known shaped articles cannot be bent.

From GB797026 a two-layer balsa wood structure for making liquefied gas tanks is disclosed. Two layers of balsa solid wood are used, the fiber directions of which are oriented perpendicular to each other. With the known two-layer arrangement, only extremely large bending radii can be produced, as occurs in liquefied gas tanks.

In addition to the aforementioned balsa wood applications, bent wood is also well known, classically known as bent plywood. The known curved wood is generally used as the central layer structure of the curved molded parts, wherein for many applications, for example in furniture construction, it is necessary to connect a plurality of initially separate, respectively multi-layered curved plywood to one another in order to achieve a sufficient wall thickness gluing, but this is flawed in many ways. On the one hand, the production process of the resulting curved molded part is more complex since several method steps are required. On the other hand, direct gluing of the curved clips without a spacer between the curved clips in practice results in a connection of relatively low stiffness.

Furthermore, the minimum bending radii achievable with the known curved wood have relatively narrow limits, so that when this small bending radius is achieved, the curved wood is damaged or a plurality of extremely thin plywood layers must be used.

In the case of existing wood materials, especially in the case of their relatively large thickness, the large reaction forces acting during the bending process are disadvantageous, because they make the further processing into curved molded parts difficult. Difficult to get.

Contents of the invention

Based on the prior art described above, the technical problem to be solved by the present invention is to provide a bent wood laminate (bent wood), which is characterized on the one hand in that manufacturing and, moreover, extremely small bending radii can be achieved without damage. Here, processability should be as simple as possible. Furthermore, the technical problem underlying the invention is to provide a molded part made of such a bent wood laminate.

The above-mentioned technical problem is solved by a bent wood laminate with the features according to claim 1 and by a molded part with the features according to claim 13 . Preferred developments of the invention are given in the dependent claims. All combinations of at least two of the features disclosed in the description, claims and/or drawings fall within the scope of the invention.

The idea of the invention is that at least one of the two outer wood layers arranged on the parallel surface sides of an intermediate layer, in particular forming a central layer, consists of peeled balsa plywood and thereby overcomes the disadvantages of the prior art curved wood laminate. An embodiment is particularly advantageous in which both outer wood layers consist of stripped balsa plywood obtained by stripping round logs. Here, the balsa trunks are preferably unprepared, i.e. wet or wet from the woods, or alternatively, the round logs, which have been preprocessed, for example by steaming or heating in a water tank, are rotated relative to the stripping knife, wherein preferably A counterpressure is expediently generated on the side facing away from the scalping knife. Here, according to the invention, the plywood has peeling cracks (in particular microcracks) originating from the peeling process, in particular sickle-shaped, which are at most regular distances on the side facing the peeling knife due to the bending of the plywood during the peeling process. produced by the load.

As mentioned, it is particularly advantageous if the balsa plywood used is peeled plywood, alternatively sliced plywood, which has peeling cracks on the side facing the knife during its manufacture, in which at least one outer wood layer, in particular It is the two outer wood layers that are arranged such that the peeling cracks face away from the middle layer and thus also from the oppositely arranged outer wood layers, that is to say on the outer sides. This arrangement of the outer wood layer on the side of the bent wood laminate that is on the inside during the bending process enables a good compression of the wood into the gap region, thereby supporting small bending radii. The arrangement of the peeling cracks after the bending process on the outside on the outer bent wood laminate side enables damage-free opening of the gap region, since in this case the peeling crack cross-section increases during bending. Overall, the peeling cracks arranged in this way increase the flexibility or even plasticity of the bent wood laminate according to the invention, especially in the case of thick bent wood laminates having a thickness of more than 12 mm or 16 mm. For the case where the outer wood layers with peeling cracks are arranged on both sides of the middle layer, it is preferred that the peeling cracks on both sides run in a common direction, ie are aligned parallel to each other.

The use of at least one outer wood layer made of peeled balsa plywood, and in particular the use of two outer wood layers made of peeled balsa plywood, leads to curved wood laminates with completely new possibilities. As a result, at least one outer wood layer of peeled balsa plywood can be constructed relatively thickly, since balsa is excellently suitable for the production of such a Thick plywood (laminate). Furthermore, the bent wood laminate according to the invention can be processed further into molded parts very well, since significantly lower reaction forces occur during the bending process than in the case of known bent clamping plates. Furthermore, peeled balsa plywood, especially if it has the aforementioned peeling cracks, is particularly flexible and can be bent with extremely small bending radii. Since curved wood laminates can now have a relatively large thickness due to the use of at least one outer wood layer consisting of peeled balsa plywood, it is not necessary to connect several bent wood laminates each with a middle layer and two outer wood layers to each other Gluing to obtain a sufficiently thick core layer for the curved molded part with defects connected thereto, but the curved molded part preferably only comprises a single bent wood layer according to the invention in the direction of its thickness extension Press panels, the bent wood laminates each having on at least one side, in particular on both sides, an in particular relatively hard or reinforcing (further preferably also decorative) covering layer.

A further advantage of the bent wood laminate constructed according to the solution of the invention or of the molded parts produced therefrom lies in the good thermal insulation properties due to the use of at least one peeled balsa wood layer.

An embodiment is particularly advantageous in which the middle layer is thinner than the two outer wood layers of peeled balsa plywood in order thereby to achieve optimized bending properties.

An embodiment of the bent wood laminate according to the invention is quite particularly advantageous, in which, in addition to the middle layer and two outer wood layers which are preferably each constructed from peeled balsa plywood (except for optionally provided , the glue layer between the middle layer and the outer wood layer, to be explained later), there is no further layer, in particular no further wood layer. As will be explained later, there are different possibilities with regard to the design of the intermediate layer. According to a first alternative, the intermediate layer is a layer different from the adhesive layer, in particular an adhesive film, for example a wood layer or a metal layer, wherein by selecting the intermediate layer the bending properties of the curved wood laminate can be influenced and/or additional Feature. According to a second alternative embodiment, the intermediate layer is a glue layer, which in particular directly connects the two outer wood layers to one another. In particular in this case the intermediate layer can be designed as an adhesive film, in particular as a thermoformable plastic film. In the case of the second variant, it is preferred that no further layers are provided besides, in particular, the only glue middle layer and the two outer wood layers, which is basically possible with the two above-mentioned replacements, For example, by externally presenting on at least one of the two outer wood layers a further bendable layer, in particular a (further) wood layer, particularly preferably a peeled balsa wood layer, which can especially be achieved by combining with the corresponding outer wood layer The layers are glued together.

In order to influence the bending behavior in a targeted manner, it is advantageously provided in a further development of the invention that at least one of the two outer wood layers, in particular on the two outer wood layers, can be provided, for example, with the aid of a cutting knife in a targeted manner. Grooves, in particular cuts or perforations provided by punching or punching, by opening the stripped balsa plywood or bending it (further). Depending on the number and orientation of the grooves, especially the cuts, the peeling cracks of the first and/or second outer wood layer can also be arranged on the side of the outer wood layer facing the middle layer, especially when the above-mentioned grooves are arranged on the respective When the surface side of the outer wood layer facing away from the middle layer is on. It is advantageous if the grooves, in particular the cuts, of the outer wood layers are aligned at least approximately parallel to each other, wherein it is particularly preferred that they are parallel to the peeling cracks of the same outer wood layer and/or parallel to possible openings of the oppositely arranged outer wood layers. Groove to arrange. However, it is also conceivable that the grooves, in particular the notches, are arranged at an angle to the peeling cracks of the respective outer wood layer, wherein preferably the grooves of the outer wood layer are parallel to the grooves of the oppositely arranged outer wood layer and/or Arranged or aligned relative to the peeling cracks of the outer wood layer arranged.

For the case where the middle layer is configured as an oriented layer, for example as a wood layer, it is preferred that the material direction, in particular the wood fibers, be at an angle to the longitudinal direction of the peeling cracks and thus to the fiber direction of the first or second outer wood layer, In particular vertically and/or at an angle, in particular perpendicularly, to a possibly provided groove, in particular notch, of at least one of the outer wood layers.

It is particularly suitable if the first and/or second outer wood layer of balsa plywood has more than 3 mm, preferably more than 4 mm, further preferably more than 6 mm, still more preferably more than 8 mm, very particularly preferably more than 10 mm layer thickness. Preferably, the layer thickness is selected from a value range between approximately 3.5 mm and approximately 12 mm or higher.

The intermediate layer preferably has a thickness resulting from a value range between 0.5 mm and 5 mm, preferably between 0.5 mm and 4 mm.

It is very particularly advantageous if the distance between the outside of the first wood layer and the outside of the second wood layer is at least 8 mm, preferably at least 10 mm, very particularly preferably at least 14 mm, still further preferably at least 16 mm. Particularly preferably, the distance is selected from a range of values between 8 mm and 25 mm, in particular between 18 mm and 30 mm. It is particularly advantageous that the aforementioned distances correspond to the total thickness of the bent wood laminate, furthermore preferably in the case of a three-layer structure comprising a middle layer and two outer wood layers, if necessary with an interposed glue layer.

Different possibilities are given regarding the specific construction of the bent wood laminate. An asymmetrical structure is thus possible in principle, in which the two outer wood layers have different thicknesses. However, a symmetrical structure is particularly preferred in which the intermediate layer forms the axis of symmetry, wherein it is quite particularly preferred that the neutral fibers of the curved wood laminate run in particular centrally in the intermediate layer.

There are also different possibilities with regard to the choice of material for the intermediate layer. It may thus consist of or contain flexible plywood, for example balsa plywood. It is also conceivable to provide additionally or preferably alternatively a textile material, in particular a textile or a mat, or an elastic or thermoplastic plastic layer, such as a plastic film, or alternatively a metallic film or foil, in addition to the plywood. An outstanding feature of the intermediate layer is good elastic or preferably plastic plasticity (flexural properties). Preferably, the material of the intermediate layer, which can also consist of a glue layer as mentioned at the outset, is selected in such a way that the properties and/or additional functionality of the bent wood laminate are influenced in a targeted manner. The intermediate layer can thus be an electrically conductive layer, in particular a metal layer as mentioned, or a layer having at least one conductor track, preferably a plurality of conductor tracks, for conducting electrical energy and/or electrical signals. It is also possible to form the intermediate layer as an information-carrying layer, in particular if the intermediate layer is magnetized at least in sections and has data in this way. It is also possible to provide memory chips and/or logic units in the intermediate layer or to embed them in the intermediate layer. The intermediate layer can also be configured as a moisture barrier, in particular in the case of an embodiment consisting of plastic and/or metal. Depending on the choice of material, the intermediate layer can also have reinforcing properties.

It is preferred that the outer wood layers in certain boundaries are flexibly connected to the middle layer, which can be achieved by choosing a suitable glue. A salient feature of the glue should be that it does not break even in the event of maximum deflection, which is important for the uniform deformation of the curved wood laminate and for the resulting stability of the resulting curved molding. A particularly good experience is with foamed one-component polyurethane adhesives. The use of a foamed adhesive here has the advantage that possible thickness fluctuations due to the relatively rough plywood surface are compensated and thus ensure a full-surface connection. It is likewise possible to use further adhesives which satisfy the above-mentioned conditions. As an alternative to foaming adhesives, in particular in the case of relatively smooth surfaces, non-foaming glues, in particular thermoformable films, which soften when heated, can also be used.

It is very particularly preferred that the inner bending radius is from the value range between 120 mm and 300 mm, preferably between 100 mm and 250 mm, preferably between 80 mm and 200 mm, still more preferably between 40 mm and 180 mm.

when the density of the first and/or second outer wood layer is below 200 kg/m ³ and preferably from a value range between 80 kg/m ³ and 165 kg/m ³ when measured at a residual moisture content of 12% of the wood weight When selected, the total weight of the bent wood laminate and subsequently of the molded part resulting therefrom is low, while at the same time giving particularly good bending results.

The invention also relates to a curved molded part, in particular for furniture or as a partition, in particular as a casing, comprising, in particular in its thickness direction, a unique, curved curved wood laminate according to the invention plan to construct. Preferably a curved wood laminate with a symmetrical structure consisting of (preferably only) two outer skinned balsa plywood outer wood layers with an intermediate layer in between. As mentioned at the outset, it can be formed as a glue layer or as a layer different from the glue layer, wherein in the latter case the intermediate layer is thus preferably connected to the outer wood layer in each case by means of the glue layer. The curved molding is also characterized in that a preferably decorative cover layer is provided on the outside of the first outer wood layer and/or on the outside of the second wood layer, which furthermore preferably makes the curved molding increase or harden. Quite particularly preferably, the curved wood laminate constructed according to the solution of the invention forms a core layer structure which is surrounded on both surface sides by at least one, in particular only one covering layer, which is preferably in each case connected to the adjacent outer wood layer glued together.

In particular, used as covering layers are: hardwood fiberboard, hardboard, medium density fiberboard, plywood, plywood, high pressure laminate (HPL), fiber composite, fiber composite plastic (FVK), fiber reinforced plastic (FRP).

As mentioned, an additional advantage of balsa plywood is its excellent deformability and ability to evenly match the smallest bend radii. The resulting material composition has low reaction forces due to the good deformability of the balsa wood plywood and additionally due to the smaller number of layers compared to the prior art, so that in the molded part no need for multiple bent wood The laminated panels are glued to each other flatly.

It is very particularly preferred that the curved molded part has an S-shaped curvature at least in one section.

Description of drawings

Further advantages, features and characteristics of the invention emerge from the following description of preferred exemplary embodiments and with reference to the drawings.

In the attached picture:

Figure 1 shows a bent wood laminate that has been bent, and

FIG. 2 shows a curved molded part produced from the curved wood laminate according to FIG. 1 .

In the figures, identical elements having the same function are identified with the same reference numerals.

Detailed ways

FIG. 1 shows a symmetrically constructed curved wood laminate 1 comprising three surface elements glued to each other. On the one hand, there is a central intermediate layer 2 that forms the axis of symmetry and accommodates the neutral fibers centrally, and is formed from a flexible substrate, such as plywood wood, plastic film, textile or metal. An outer wood layer 3 , 4 is located on each surface side of the middle layer 2 , wherein, for example, it is denoted with reference numeral 3 and is constructed as peeled balsa plywood The first outer wood layer and the outer wood layer that is also configured as peeled balsa plywood is designated with the reference number 4 .

The two outer wood layers 3, 4 are respectively glued to the middle layer 2 through an unmarked glue layer.

It can be seen that the two outer wood layers 3 , 4 have a so-called peeling crack 5 on the outside, which is caused by production and which results from the production of the plywood, and more precisely on the side facing the stripping knife.

The arrangement shown is particularly advantageous, wherein the peeling cracks of the two outer wood layers 3, 4 have the same orientation and are located on the respective outer sides, that is to say on the side facing away from the middle layer 2, so that the initially unbent, ie The planar curved wood laminate can be bent about a virtual bending axis which runs parallel to the longitudinal direction of the peeling crack 5 .

During this bending, the balsa of the inner curved layer (in the exemplary embodiment shown, the second outer wood layer 4 ) compresses, which is optimally achieved by peeling cracks 5 . At the same time, the peeling cracks 5 of the outer bending layer (that is to say the first outer wood layer 3 in the exemplary embodiment shown) are stretched or expanded, resulting in an optimal bending behavior in combination. In the exemplary embodiment shown, only the inner bending radius R is indicated. In the case of an outer bending radius, the marked arrow should continue to the outside of the first outer wood layer 3 .

For the case where the middle layer 2 is a wood layer, such as a balsa plywood layer, it is preferred that the fiber orientation and/or possibly provided peeling cracks of the middle layer 2 be at an angle, for example perpendicularly, to the peeling cracks of the outer wood layers 3, 4 extended.

An initially planar, i.e. unbent, bent wood such as that shown in FIG. 1 after fabrication in a press, which can be transformed into the curved shape shown in FIG. A curved molding 6 is shown in FIG. 2 , where the curved wood laminate 1 forms a core layer arrangement (central arrangement) accommodated between two covering layers 7 , 8 . The connection of the bent wood 1 and the covering layers 7 , 8 is preferably carried out between two formworks, the inner formwork abutting against the first surface side and the second formplatte adhering to the second surface side. That is to say, for example, a mold (Form) and a counterpart mold (Gegenform) are used, which apply a pressing pressure (Pressdruck) to optimize the gluing process. Alternatively, the layer structure is glued, brought into a mold, and negative pressure is applied, for example in a vacuum bag. Here, the cover layers 7 , 8 are preferably glued to the bent wood laminate 1 . It can be seen that the molding 6 has a single curved wood laminate 1 in its thickness direction, which is preferred. In other words, it is not necessary, as in the prior art, to laminate a plurality of bent wood laminates to one another in order to achieve the desired overall thickness of the molded part 6 . For the sake of clarity, the peeling cracks of the bent wood laminate 1 are not shown in the illustration according to FIG. 2 .

In the exemplary embodiment shown, the thickness a of the two outer wood layers 3 , 4 is each 10 mm. The intermediate layer 2 has a thickness b of, for example, 1 mm. This results in a thin adhesive layer with a total thickness of the bent wood laminate 1 of 21 mm plus an average thickness of preferably less than 1 mm, in particular between 0.1 mm and 0.5 mm.

List of reference signs

1 bent wood laminate

2 middle layers

3 first outer wood layer

4 second outer wood layer

5 peeling cracks

6 curved moldings

7 overlays

8 overlays

a thickness - outer wood layer

bThickness - middle layer

R inner bending radius

Claims (15)

1. one kind has the flexible bending-wood laminate in the intermediate layer (2) particularly forming central stratum, there are the first and second face side, first outer timber layer (3) is wherein set on first surface side and the second outer timber layer (4) is set on second surface side

It is characterized in that,

Described first and/or second outer timber layer (3,4) is made up of peeling cork wood glued board, and

Described first and/or second outer timber layer (3,4) there is peeling crackle (5) in face side, and the described first and/or second outer timber layer (3,4) be arranged to, there is the face side of described peeling crackle (5) dorsad intermediate layer (2).

2. bending-wood laminate according to claim 1, is characterized in that, described intermediate layer (2) have the thickness less than described first and second outer timber layer (3,4).

3. bending-wood laminate according to claim 1 and 2, it is characterized in that, the described first and/or second outer timber layer (3,4) has particularly by the groove that cutter are made in face side, preferred otch or perforation, for affecting flexural property.

4. the bending-wood laminate according to any one of the claims, it is characterized in that, described first and/or second outer timber layer (3,4) has more than 3mm, preferably more than 4mm, preferred more than 6mm further, also preferred more than 8mm further, completely particularly preferably more than 10mm, the also preferred thickness more than 12mm further, particularly between 3.5mm and 12mm, the thickness obtained in the codomain preferably between 8mm and 14mm.

5. the bending-wood laminate according to any one of the claims, it is characterized in that, distance between the outside of the first timber layer and the outside of the second timber layer, this distance, preferably corresponding to the gross thickness of bending-wood laminate (1), is at least 8mm, preferably at least 10mm, preferred at least 14mm, completely particularly preferably at least 16mm, and completely particularly preferably between 8mm and 25mm, in the codomain particularly between the 30mm of 18mm, select this distance.

6. the bending-wood laminate according to any one of the claims, is characterized in that, the neutral fibre, particularly Central places of bending-wood laminate (1), extends in described intermediate layer (2).

7. the bending-wood laminate according to any one of the claims, is characterized in that, described intermediate layer (2) have between 0.3mm and 5mm, the thickness obtained in the codomain preferably between 0.5mm and 4mm.

8. the bending-wood laminate according to any one of the claims, it is characterized in that, described intermediate layer (2) comprises glued board, the textile material of Yi Qu, preferably textile product or mat, plastic layer, sheet metal or glue-line, particularly glued membrane, or described intermediate layer (2) are made up of above-mentioned material.

9. the bending-wood laminate according to any one of the claims, it is characterized in that, in intermediate layer (2) and outer timber layer (3,4) that particularly foam, preferably easily bent glue-line is set between respectively, particularly preferred one-component polyurethane adhesive, or plastic plastic sheeting after heat.

10. the bending-wood laminate according to any one of the claims, it is characterized in that, described bending-wood can with between 120mm and 300mm, preferably between 100mm and 250mm, preferably between 80mm and 200mm, the inner bend radius that the codomain particularly preferably between 40mm and 180mm obtains is bent and/or is flexible.

11. bending-wood laminates according to any one of the claims, is characterized in that, the density of the described first and/or second outer timber layer (3,4), when to remain moisture content be 12% of wooden weight, lower than 200kg/m ³and preferably from 80kg/m ³and 165kg/m ³between codomain in select.

12. bending-wood laminates according to any one of the claims, is characterized in that, described bending-wood laminate is made up of two outer timber layer (3,4) and intermediate layer (2) and the glue-line be between them.

13. 1 kinds of bending moulded parts, especially for the dividing plate of furniture or such as hull shape, comprise particularly unique, that be bent, bending-wood laminate (1) according to any one of the claims, wherein in the first and/or second outer timber layer (3,4) outside is arranged preferred ornamental cover layer (7,8).

14. moulded parts according to claim 13, is characterized in that, described cover layer (7,8) constructs and is arranged as and moulded parts is strengthened.

15. moulded parts according to claim 13 or 14, it is characterized in that, described cover layer (7,8) comprises or is made up of the material in following group: hardwood fiber plate, hard fiber board, medium density fibre board (MDF), glued board, clamping plate, high-pressure laminate (HPL), fibrous composite (FVK), fibre reinforced plastics (FRP).